- Patients must not have any prior exposure to immunotherapy such as, but not limited to anti-programmed death 1 (PD-1) or anti-PD-L1 antibodies; prior exposure to the following is allowed: anti-cytotoxic T lymphocyte antigen 4 (CTLA-4) antibodies, live attenuated vaccines, anti-EGFR agents and sargramostim (GM-GSF)